Hi Paul C:
Aren't you implicitly assuming that SNLT in 1860 Germany equals SNLT
in Japan in the 1990s?
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Distinguish two things here - necessity of labour with respect
to the market on which a commodity is sold - and expenditure
of labour as a fraction of the workers life.
The SNLT criterion applies to comparing two different contemporaneous
labours, one efficient one less so. But the labour theory of value also
allows one to
compare products to peoples real lives.
It gives a basis to evaluate objectively economic progress.
If a kilo of rice in China today involves less necessary labour
than it did 100 years ago, that is an objective advancement
in productivity.
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Aren't you also implicitly assuming that the
intensity of labor hasn't changed temporally and spatially?
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To a first approximation yes, you are clearly right that
one might later attempt to compensate for this.
> 2. changes in the value of specific commodities across space and time
-
> a kilo of rice for example
How does the change in the value of _one_ commodity (in this case,
rice)
allow us to determine the commensurability of _all_ commodities?
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Issue is not commensurability of commodities per se, but the
comparison of commodities to the expenditure of human lifetimes.
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> 3. changes in the rate of surplus value across space and time
See my questions under 1.
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Since rate of surplus value is a dimensionless ratio, I don't
see that those issue above apply